Display device

ABSTRACT

A display device can include a first substrate having an upper surface which is a display surface and a lower surface facing the upper surface; an active layer disposed on a lower surface of the first substrate and including a channel part, a first connection part connected to one side of the channel part, and a second connection part connected to the other side of the channel part; a gate electrode disposed under the active layer and overlapping with the channel part; a second substrate disposed under the above gate electrode; a liquid crystal layer disposed between the first substrate and the second substrate; and a backlight provided under the second substrate. Also, the gate electrode can be disposed between a lower surface of the channel part of the active layer and the backlight, in order to protect the channel part from light emitted from the backlight.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the priority benefit of the Korean PatentApplication No. 10-2022-0038954 filed in the Republic of Korea on Mar.29, 2022, and Korean Patent Application No. 10-2022-0132652 filed in theRepublic of Korea on Oct. 14, 2022, all of these applications beinghereby expressly incorporated by reference as if fully set forth hereininto the present application.

BACKGROUND Technical Field

The present disclosure relates to a display device.

Description of the Related Art

Display devices, such as liquid crystal display device or organic lightemitting device, include a substrate equipped with thin film transistorsas switching or driving elements.

A separate driving element is connected to an outer part of thesubstrate to drive the thin film transistor, and for this reason, a sizeof a bezel of the display device is increased. Large bezel areas arounda display are often undesirable and take up additional space.

Also, in order to reduce or eliminate the bezel size of the displaydevice, the substrate was placed upside down so that an opposite surfaceof the substrate on which the thin film transistor is not provided isconfigured to be a display surface.

However, for example, when the substrate is upside down in a liquidcrystal display device, a light emitted from a backlight placed underthe substrate can shine on a channel part of an active layerconstituting the thin film transistor, which can degrade the channelpart over time. In addition, to solve this problem, a light shieldinglayer can be added to cover the channel part of the active layer forprotection, but in this situation, there is a problem that the apertureratio of the display device decreases and image quality can becomeimpaired, and the configuration becomes more complicated and increasesmanufacturing time and costs.

SUMMARY OF THE DISCLOSURE

The present disclosure has been made in view of the above problems, andit is an object of the present disclosure to provide a display devicecapable of preventing light from directly irradiating and damaging achannel part of an active layer even if a substrate equipped with a thinfilm transistor is disposed upside down.

In accordance with an aspect of the present disclosure, the above andother objects can be accomplished by the provision of a display deviceincluding a first substrate having an upper surface which is a displaysurface and a lower surface facing the upper surface; an active layerprovided on the lower surface of the first substrate and including achannel part, a first connection part connected to one side of thechannel part, and a second connection part connected to the other sideof the channel part; a gate electrode provided under the active layerand overlapping the channel part; a second substrate provided under thegate electrode; a liquid crystal layer provided between the firstsubstrate and the second substrate; and a backlight provided under thesecond substrate, in which light emitted from the backlight is blockedby the gate electrode after passing through the second substrate and theliquid crystal layer, and prevented from entering into or on the channelpart.

In accordance with another aspect of the present disclosure, the aboveand other objects can be accomplished by the provision of a displaydevice including a first substrate having an upper surface which is adisplay surface and a lower surface facing the upper surface; an activelayer provided on the lower surface of the first substrate and includinga channel part, a first connection part connected to one side of thechannel part, and a second connection part connected to the other sideof the channel part; a gate electrode spaced apart from the active layerand overlapping the channel part; a source electrode connected to thefirst connection part of the active layer; a drain electrode connectedto the second connection part of the active layer; and a pixel electrodeconnected to the drain electrode, in which the active layer is providedbetween the first substrate and the gate electrode.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and other advantages of thepresent disclosure will be more clearly understood from the followingdetailed description taken in conjunction with the accompanyingdrawings, in which:

FIG. 1 is a plan view illustrating a display device according to oneembodiment of the present disclosure;

FIG. 2 is a schematic cross-sectional view of the display deviceaccording to one embodiment of the present disclosure, which correspondsto a cross-sectional view along A-A′ line of FIG. 1 ;

FIG. 3 is a schematic cross-sectional view of the display deviceaccording to another embodiment of the present disclosure, whichcorresponds to a cross-sectional view along A-A′ line of FIG. 1 ;

FIG. 4 is a schematic cross-sectional view of the display deviceaccording to another embodiment of the present disclosure, whichcorresponds to a cross-sectional view along A-A′ line of FIG. 1 ;

FIG. 5 is a schematic cross-sectional view of the display deviceaccording to still another embodiment of the present disclosure, whichcorresponds to a cross-sectional view along A-A′ line of FIG. 1 ;

FIG. 6 is a plan view illustrating a display device according to anembodiment of the present disclosure;

FIG. 7 is a plan view illustrating a display device according to anotherembodiment of the present disclosure;

FIG. 8 is a plan view illustrating a display device according to stillanother embodiment of the present disclosure;

FIG. 9 is a plan view illustrating a display device according to stillanother embodiment of the present disclosure;

FIG. 10 is a plan view illustrating a display device according to stillanother embodiment of the present disclosure;

FIG. 11 is a plan view illustrating a display device according to stillanother embodiment of the present disclosure;

FIG. 12 is a plan view illustrating a display device according to stillanother embodiment of the present disclosure;

FIG. 13 is a schematic cross-sectional view of the display deviceaccording to still another embodiment of the present disclosure, whichcorresponds to a cross-sectional view along A-A′ line of FIG. 12 ;

FIG. 14 is a schematic cross-sectional view of the display deviceaccording to still another embodiment of the present disclosure, whichcorresponds to a cross-sectional view along A-A′ line of FIG. 12 ;

FIG. 15 is a plan view illustrating a display device according to stillanother embodiment of the present disclosure.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Reference will now be made in detail to embodiments of the presentdisclosure, examples of which can be illustrated in the accompanyingdrawings. In the following description, when a detailed description ofwell-known functions or configurations related to this document isdetermined to unnecessarily cloud a gist of the inventive concept, thedetailed description thereof will be omitted. The progression ofprocessing steps and/or operations described is an example; however, thesequence of steps and/or operations is not limited to that set forthherein and can be changed as is known in the art, with the exception ofsteps and/or operations necessarily occurring in a particular order.Like reference numerals designate like elements throughout. Names of therespective elements used in the following explanations are selected onlyfor convenience of writing the specification and can be thus differentfrom those used in actual products.

Advantages and features of the present disclosure, and implementationmethods thereof will be clarified through following embodimentsdescribed with reference to the accompanying drawings. The presentdisclosure can, however, be embodied in different forms and should notbe construed as limited to the embodiments set forth herein. Rather,these embodiments are provided so that this disclosure will be thoroughand complete, and will fully convey the scope of the present disclosureto those skilled in the art.

A shape, a size, a ratio, an angle, and a number disclosed in thedrawings for describing embodiments of the present disclosure are merelyan example, and thus, the embodiments of the present disclosure are notlimited to the illustrated details. Like reference numerals refer tolike elements throughout. In the following description, when thedetailed description of the relevant known function or configuration isdetermined to unnecessarily obscure the important point of the presentdisclosure, the detailed description will be omitted. In a situationwhere “comprise,” “have,” and “include” described in the presentspecification are used, another part can be added unless “only” is used.The terms of a singular form can include plural forms unless referred tothe contrary.

In construing an element, the element is construed as including an errorrange although there is no explicit description.

In describing a position relationship, for example, when a positionrelation between two parts is described as “on,” “over,” “under,” and“next,” one or more other parts can be disposed between the two partsunless a more limiting term, such as “just” or “direct(ly)” is used.

In describing a time relationship, for example, when the temporal orderis described as, for example, “after,” “subsequent,” “next,” and“before,” a situation which is not continuous can be included unless amore limiting term, such as “just,” “immediate(ly),” or “direct(ly)” isused.

It will be understood that, although the terms “first,” “second,” etc.,can be used herein to describe various elements, these elements shouldnot be limited by these terms. These terms are only used to distinguishone element from another. For example, a first element could be termed asecond element, and, similarly, a second element could be termed a firstelement, without departing from the scope of the present disclosure.

In describing the elements of the present disclosure, terms such asfirst, second, A, B, (a), (b), etc., can be used. Such terms are usedfor merely discriminating the corresponding elements from other elementsand the corresponding elements are not limited in their essence,sequence, or precedence by the terms. It will be understood that when anelement or layer is referred to as being “on” or “coupled to” anotherelement or layer, it can be directly on or directly coupled to the otherelement or layer, or intervening elements or layers can be present.Also, it should be understood that when one element is disposed on orunder another element, this can denote a situation where the elementsare disposed to directly contact each other, but can denote that theelements are disposed without directly contacting each other.

The term “at least one” should be understood as including any and allcombinations of one or more of the associated listed elements. Forexample, the meaning of “at least one of a first element, a secondelement, and a third element” denotes the combination of all elementsproposed from two or more of the first element, the second element, andthe third element as well as the first element, the second element, orthe third element.

The term “surround” as used herein includes at least partiallysurrounding as well as entirely surrounding one or more of theassociated elements. Similarly, the term “cover” as used herein includesat least partially covering as well as entirely covering one or more ofthe associated elements. For example, if an encapsulation layersurrounds a dam, this can be construed as the encapsulation layer atleast partially surrounding the dam. However, in some embodiments, theencapsulation layer can entirely surround the dam. The meaning in whichthe term “surround” is used herein can be further specified based on theassociated drawings and embodiments. In the present disclosure, theterms “surround,” “at least partially surround,” “completely surround”or the like is used. In accordance with the definition of “surround” asset forth above, when only the term “surround” is used in an embodiment,it can mean either at least partially surrounding or entirelysurrounding one or more of the associated elements. The same applies forthe term “cover.”

Features of various embodiments of the present disclosure can bepartially or overall coupled to or combined with each other, and can bevariously inter-operated with each other and driven technically as thoseskilled in the art can sufficiently understand. The embodiments of thepresent disclosure can be carried out independently from each other, orcan be carried out together with in co-dependent relationship.

Hereinafter, embodiments of the present disclosure will be described indetail with reference to the accompanying drawings. In adding referencenumerals to elements of each of the drawings, although the same elementsare illustrated in other drawings, like reference numerals can refer tolike elements. Also, for convenience of description, a scale of each ofelements illustrated in the accompanying drawings differs from a realscale, and thus, is not limited to a scale illustrated in the drawings.

FIG. 1 is a schematic plan view of a display device according to oneembodiment of the present disclosure, which illustrates only onesub-pixel of the display device.

As shown in FIG. 1 , the display device according to one embodiment ofthe present disclosure includes a gate line 150, a data line 110, a thinfilm transistor T, a first light blocking layer 115, a connectionelectrode 153, a pixel electrode 190, and a second light blocking layer210.

The gate line 150 and the data line 110 are arranged to cross each otherto define a pixel area. The gate line 150 can be arranged in a firstdirection, for example, a horizontal direction, and the data line 110can be arranged in a second direction, for example, a verticaldirection.

The thin film transistor T is provided near an intersection regionbetween the gate line 150 and the data line 110. The thin filmtransistor T includes a gate electrode 151, an active layer 130, asource electrode 111, and a drain electrode 152.

The gate electrode 151 can protrude from the gate line 150.Specifically, the gate electrode 151 protrudes from the gate line 150 inthe second direction, for example, in a vertical direction. For example,the gate electrode 151 can protrude from the gate line 150 in a samedirection as the data line 110. The gate electrode 151 and the gate line150 can be formed of a same material on a same layer as one body througha same process.

The active layer 130 is provided to overlap the gate electrode 151, thesource electrode 111, and the drain electrode 152. Specifically, one endof the active layer 130 overlaps the source electrode 111, the other endof the active layer 130 overlaps the drain electrode 152, and a portionbetween one end and the other end of the active layer 130 overlaps thegate electrode 151.

The source electrode 111 is formed as a portion of the data line 110.However, the present invention is not limited thereto, and the sourceelectrode 111 can protrude from the data line 110. The source electrode111 and the data line 110 can be formed as one body. A width of thesource electrode 111 in the first direction, for example, in thehorizontal direction, can be greater than a width of other parts of thedata line 110 except for the source electrode 111 to facilitate anelectrical connection between the source electrode 111 and the activelayer 130 (e.g., the data line 110 can have a pad area for connection tothe active layer 130). The source electrode 111 can be connected to theactive layer 130 through a first contact hole CH1. In addition, thesource electrode 111 can be connected to the connection electrode 153through the second contact hole CH2.

The drain electrode 152 can be located near the gate electrode 151. Thedrain electrode 152 is connected to the pixel electrode 190 through athird contact hole CH3.

The first light blocking layer 115 overlaps at least a portion of thegate electrode 151, and particularly, overlaps a portion of the activelayer 130, more specifically, a channel part 131 of the active layer130. The first light blocking layer 115 can overlap the channel part 131of the active layer 130 to prevent light from being incident on thechannel part 131. The first light blocking layer 115 can be formed notto overlap the gate line 150 and the data line 110. In addition, thefirst light blocking layer 115 can be formed so as not to overlap thesource electrode 111 and the drain electrode 152. The first lightblocking layer 115 can be formed of a conductive material.

The connection electrode 153 is formed to overlap the source electrode111 and the active layer 130. The connection electrode 153 can connectthe source electrode 111 and the active layer 130 to each other, and tothis end, the connection electrode 153 can be connected to each of thesource electrode 111 and the active layer 130. In particular, theconnection electrode 153 can be connected to the source electrode 111through a second contact hole CH2.

The pixel electrode 190 is provided in a pixel area defined by the gateline 150 and the data line 110. The pixel electrode 190 is connected tothe drain electrode 152 through a third contact hole CH3. The pixelelectrode 190 can have a structure having a plurality of slits, and thusa fringe field can be formed between the pixel electrode 190 and acommon electrode.

The second light blocking layer 210 can extend in the same seconddirection as an arrangement direction of the data line 110 whileoverlapping the data line 110 (e.g., the second light blocking layer 210can cover the data line 110). The width of the second light blockinglayer 210 in the horizontal direction can be greater than the width ofthe data line 110 in the horizontal direction, and thus the entireportion of the data line 110 can overlap the second light blocking layer210. The light blocking layer 210 is provided to overlap the data line110, which is a boundary area between sub-pixels emitting differentcolors, thereby preventing the light from mixing between the sub-pixelsemitting different colors.

According to an embodiment of the present disclosure, since the channelpart 131 of the active layer 130 is covered by the first light blockinglayer 115 and the gate electrode 151, the second light blocking layer210 does not need to additionally cover the channel part 131 of theactive layer 130. Accordingly, the second light-shielding layer 210 canbe formed so as not to overlap with the channel part 131 of the activelayer 130, the first light-shielding layer 115, and the gate electrode151. In addition, the second light shielding layer 210 can be formed soas not to overlap with the gate line 150.

FIG. 2 is a schematic cross-sectional view of the display deviceaccording to one embodiment of the present disclosure, which correspondsto a cross-sectional view along A-A′ line of FIG. 1 .

As shown in FIG. 2 , the display device according to one embodiment ofthe present disclosure includes a first substrate 100, a secondsubstrate 200, and a backlight 300.

The first substrate 100 can be formed of a thin film transistorsubstrate, and the second substrate 200 can be formed of a color filtersubstrate.

The first substrate 100 can be disposed above the second substrate 200and the backlight 300, the second substrate 200 can be disposed betweenthe first substrate 100 and the backlight 300, and the backlight 300 canbe disposed below the first substrate 100 and the second substrate 200.Accordingly, the light emitted from the backlight 300 passes through thesecond substrate 200 and the first substrate 100 sequentially and thenis emitted to the outside through an upper surface of the firstsubstrate 100. The upper surface of the first substrate 100 becomes asurface on which an image is displayed (e.g., upper surface of the firstsubstrate 100 can face toward a viewer).

At least one of the first substrate 100 and the second substrate 200 canbe made of glass or plastic. At least one of the first substrate 100 andthe second substrate 200 can be made of transparent plastic havingflexible properties, such as polyimide. When polyimide is used as atleast one of the first substrate 100 and the second substrate 200,heat-resistant polyimide that can withstand high temperatures can beused, considering that a high-temperature deposition process isperformed on the first substrate 100 and the second substrate 200.

A first light shielding layer 115, a data line 110, and a sourceelectrode 111 are provided on a lower surface of the first substrate100. The first light blocking layer 115, the data line 110, and thesource electrode 111 can be patterned on the same layer with the samematerial through the same process. Accordingly, the first light blockinglayer 115 is made of a conductive material. The data line 110 and thesource electrode 111 are formed in one body, and are insulated from thefirst light blocking layer 115 (e.g., the first light blocking layer 115is spaced apart from the data line 110 and the source electrode 111).The upper surface of the first substrate 100 corresponds to a displaysurface, and the lower surface of the first substrate 100 corresponds toa surface opposite to the display surface.

A buffer layer 120 is formed on a bottom surface of the first lightblocking layer 115, the data line 110, and the source electrode 111. Thebuffer layer 120 can protect the active layer 130 by blocking air andmoisture. The buffer layer 120 can be formed of an inorganic insulatingmaterial, such as silicon oxide, silicon nitride, or metal oxide, but isnot limited thereto and can be formed of an organic insulating material.The buffer layer 120 can be formed of a single layer or a plurality oflayers.

The buffer layer 120 is provided with a first contact hole CH1 and asecond contact hole CH2. The first contact hole CH1 and the secondcontact hole CH2 can be spaced apart from each other, and apredetermined region of the source electrode 111 can be exposed by thefirst contact hole CH1 and the second contact hole CH2.

An active layer 130 is formed on a lower surface of the buffer layer120. The active layer 130 can include a channel part 131, a firstconnection part 132, and a second connection part 133. The firstconnection part 132 can be connected to one side of the channel part 131and the second connection part 133 can be connected to the other side ofthe channel part 131.

The channel part 131 is made of a semiconductor material and overlapsthe first light blocking layer 115 and the gate electrode 151.Specifically, the first light shielding layer 115 is provided above thechannel part 131 and the gate electrode 151 is provided below thechannel part 131. Accordingly, external light incident downward towardthe channel part 131 is blocked by the first light shielding layer 115,and light emitted from the backlight 300 incident upward toward thechannel part 131 after passing through the second substrate 200 isblocked by the gate electrode 151. In this way, the channel part 131 canbe protected from both sides since the channel part 131 is sandwichedbetween the gate electrode 151 (e.g., which can protect form internallight coming from the backlight 300) and the first light shieling layer115 (e.g., which can protect from external light, such as sunlight).

The first connection part 132 and the second connection part 133 canhave conductive characteristics by selectively conducting asemiconductor material. The first connection part 132 and the secondconnection part 133 may not overlap the gate electrode 151. The firstconnection part 132 and the second connection part 133 have superiorconductivity compared to the channel part 131, and each of them canserve as a wiring or a source/drain electrode. The first connection part132 can be connected to the source electrode 111 provided above throughthe first contact hole CH1 provided in the buffer layer 120, and thesecond connection part 133 can be directly connected to the drainelectrode 152 provided below.

The active layer 130 can include a semiconductor material, for example,an oxide semiconductor material. The oxide semiconductor material is,for example, an IZO (InZnO)-based oxide semiconductor material, an IGO(InGaO)-based oxide semiconductor material, an ITO (InSnO)-based oxidesemiconductor material, an IGZO (InGaZnO)-based oxide material, an IGZTO(InGaZnSnO)-based oxide material, a GZTO (GaZnSnO)-based semiconductormaterial, a GZO (GaZnO)-based semiconductor material, an ITZO(InSnZnO)-based semiconductor material, and an FIZO (FeInZnO)-basedsemiconductor material oxide.

A gate insulating layer 140 is formed on a lower surface of the activelayer 130, particularly, on a lower surface of the channel part 131 ofthe active layer 130. The gate insulating layer 140 insulates the activelayer 130 from the gate electrode 151. The gate insulating layer 140 canbe formed in the same pattern as the gate electrode 151 (e.g., gateinsulating layer 140 and gate electrode 151 can have a same shape andsame width), but is not limited thereto. The gate insulating layer 140can overlap the channel part 131 and may not overlap the first andsecond connection parts 132 and 133. Alternatively, the gate insulatinglayer 140 can overlap the channel part 131, a portion of the firstconnection part 132, and a portion of the second connection part 133.

A gate electrode 151 is formed on a lower surface of the gate insulatinglayer 140, and a connection electrode 153 and a drain electrode 152 areformed on a lower surface of the first connection part 132 and thesecond connection part 133 of the active layer 130.

The gate electrode 151, the connection electrode 153, and the drainelectrode 152 can be formed of the same material through the sameprocess. The gate electrode 151, the connection electrode 153, and thedrain electrode 152 can be formed of a single metal layer, or can beformed of a multi-layer metal layer.

The gate electrode 151 is spaced apart from the active layer 130 withthe gate insulating layer 140 interposed therebetween, and is formed tooverlap the channel part 131 of the active layer 130 and the first lightblocking layer 115.

The connection electrode 153 can connect the source electrode 111 withthe first connection part 132 of the active layer 130. Although thesource electrode 111 and the first connection part 132 of the activelayer 130 are directly connected through the first contact hole CH1,electrical connection characteristics between the source electrode 111and the first connection part 132 of the active layer 130 can beimproved by additionally forming the connection electrode 153. However,it is also possible to omit the connection electrode 153. One side ofthe connection electrode 153 contacts the source electrode 111 throughthe second contact hole CH2 provided in the buffer layer 120, and theother side of the connection electrode 153 is directly provided on thefirst connection part 132 of the active layer 130 to contact the lowersurface of the first connection part 132. Also, the gate insulatinglayer 140 can be additionally provided on the upper surface of theconnection electrode 153, and in this situation, the gate insulatinglayer 140 additionally provided on the upper surface of the connectionelectrode 153 does not cover at least a part of the second contact holeCH2 so that the connection electrode 153 contacts the source electrode111 through the second contact hole CH2. In addition, the gateinsulating film 140 additionally provided on the upper surface of theconnection electrode 153 is provided so as not to cover at least a partof the first connection part 132 of the active layer 130 so that theconnection electrode 153 can contact the first connection part 132 ofthe active layer 130 (e.g., see FIG. 3 ).

The drain electrode 152 is provided directly on the bottom surface ofthe second connection part 133 of the active layer 130 to contact thebottom surface of the second connection part 133. Accordingly, the drainelectrode 152 is positioned below the active layer 130. On the otherhand, the source electrode 111 is located above the active layer 130 andcontacts the upper surface of the first connection part 132 of theactive layer 130. Accordingly, the source electrode 111 can bepositioned between the first substrate 100 and the active layer 130, andthe drain electrode 152 can be positioned between the active layer 130and the pixel electrode 190. As described above, the drain electrode 152and the source electrode 111 are provided at different positions and canbe made of different materials. For example, the source electrode 111and the drain electrode 152 can be located at opposite sides of thetransistor (e.g., one at an upper side, and the other at an lower side).Also, the gate insulating layer 140 can be additionally provided on theupper surface of the drain electrode 152, and in this situation, thegate insulating layer 140 additionally provided on the upper surface ofthe drain electrode 152 may not cover at least a part of the secondconnection part 133 of the active layer 130 so that the drain electrode152 can contact the second connection part 132 of the active layer 130.

A passivation layer 161 is formed on the bottom surface of the gateelectrode 151, the connection electrode 153, and the drain electrode152, and a planarization layer 162 is formed on the bottom surface ofthe passivation layer 161.

The passivation layer 161 can include a single layer or multiple layersincluding an inorganic insulating material and/or an organic insulatingmaterial, and the planarizing layer 162 can be formed of an organicinsulating material thicker than the passivation layer 161.

A third contact hole CH3 is provided in the passivation layer 161 andthe planarization layer 162, so that the lower surface of the drainelectrode 152 can be exposed by the third contact hole CH3.

A common electrode 170 is formed on a lower surface of the planarizationlayer 162. The common electrode 170 is made of a transparent conductivematerial, and is not formed in the third contact hole CH3 region toprevent a short circuit with the pixel electrode 190 in the thirdcontact hole CH3. Accordingly, the common electrode 170 can be formed onthe entire lower surface of the planarization layer 162 except for thethird contact hole CH3 region.

A common wiring 175 is formed on a lower surface of the common electrode170. Since the common wiring 175 can be made of a metal material, aproblem of low resistance of the common electrode 170 can be improvedand a voltage drop can be prevented. The common wiring 175 is formed tooverlap the data line 110 so that an aperture ratio is not reduced dueto the addition of the common wiring 175.

An interlayer insulating layer 180 is formed on a lower surface of thecommon wiring 175. The interlayer insulating layer 180 is formed betweenthe common electrode 170 and the pixel electrode 190 to insulate thecommon electrode 170 from the pixel electrode 190. The interlayerinsulating layer 180 can extend along a side surface of the thirdcontact hole CH3, but can be provided so that at least a part of thedrain electrode 152 is exposed.

A pixel electrode 190 is formed on a lower surface of the interlayerinsulating layer 180. The pixel electrode 190 extends along the thirdcontact hole CH3 and is connected to the drain electrode 152.

A second light blocking layer 210 is formed on an upper surface of thesecond substrate 200, which is a surface facing the first substrate 100.The second light blocking layer 210 can be formed of a black material,but is not limited thereto. The second light shielding layer 210 can beformed to overlap the data line 110 to prevent the light from mixingbetween sub-pixels in the area of the data line 110.

Color filters 221 and 222 are formed on the upper surface of the secondlight blocking layer 210. The color filters 221 and 222 include a firstcolor filter 221 that transmits light of a first color and a secondcolor filter 222 that transmits light of a second color. The first colorfilter 221 is provided in the first sub-pixel, and the second colorfilter 222 is provided in the second sub-pixel. The first color filter221 and the second color filter 222 can overlap each other in the dataline 110 area, which is a boundary area between the first sub-pixel andthe second sub-pixel. Accordingly, mixed light can occur in the dataline 110 area, but since light emitted from the backlight 300 is blockedby the second light blocking layer 210, the mixed light can be preventedin the data line 110 area.

As described above, since the light emitted from the backlight 300 canbe blocked by the gate electrode 151 to protect the channel part 131 ofthe active layer 130, the second light shielding layer 210 can be formedso as not to overlap with the gate electrode 151 and the channel part131 of the active layer 130.

The backlight 300 emits light toward the second substrate 200, andvarious types of backlights can be applied, such as edge type or directtype.

The light emitted from the backlight 300 passes from the secondsubstrate 200 to the gate electrode 151 on the first substrate 100, butfurther progress is blocked by the gate electrode 151 so that thechannel part 131 of the active layer 130 on the gate electrode 151 canbe protected from light emitted from the backlight 300.

In addition, a liquid crystal layer is additionally provided between thefirst substrate 100 and the second substrate 200, and the liquid crystallayer can be sealed by a sealant provided at the edges of the firstsubstrate 100 and the second substrate 200. In addition, a spacer formaintaining a cell gap, for example, a column spacer, can be providedbetween the first substrate 100 and the second substrate 200.

FIG. 3 is a schematic cross-sectional view of the display deviceaccording to the other embodiment of the present disclosure, whichcorresponds to a cross-sectional view along A-A′ line of FIG. 1 .

FIG. 3 is the same as the display device according to FIG. 2 except thatthe structure of the gate insulating layer 140 is changed (e.g., thegate insulating layer 140 is larger and extends farther). Therefore, thesame reference numerals are assigned to the same configuration, and onlydifferent configurations will be described below.

As shown in FIG. 3 , according to another embodiment of the presentdisclosure, the gate insulating layer 140 is formed not only on theregion between the gate electrode 151 and the channel part 131 of theactive layer 130, but also on the lower surface of the first connectionpart 132 of the active layer 130 and a lower surface of the secondconnection part 133 of the active layer 130 and the lower surface of thebuffer layer 120.

Also, same as in FIG. 2 , the gate insulating layer 140 can beadditionally provided on the upper surface of the connection electrode153, and in this situation, the gate insulating layer 140 additionallyprovided on the upper surface of the connection electrode 153 isprovided not to cover at least a part of the second contact hole CH2 sothat the connection electrode 153 contacts the source electrode 111through the second contact hole CH2. In addition, the gate insulatinglayer 140 additionally provided on the upper surface of the connectionelectrode 153 is provided not to cover at least a part of the firstconnection part 132 of the active layer 130 so that the connectionelectrode 153 can contact the first connection part 132 of the activelayer 130.

In addition, the gate insulating layer 140 can be additionally providedon the upper surface of the drain electrode 152. The gate insulatingfilm 140 additionally provided on the upper surface of the drainelectrode 152 is provided not to cover at least a part of the secondconnection part 133 of the active layer 130 so that the drain electrode152 can contact the second connection part 133 of the active layer 130.

FIG. 4 is a schematic cross-sectional view of the display deviceaccording to another embodiment of the present disclosure, whichcorresponds to a cross-sectional view along A-A′ line of FIG. 1 .

FIG. 4 is the same as the display device according to FIG. 2 except thata conductive layer 135 is additionally provided. Therefore, the samereference numerals are assigned to the same configuration, and onlydifferent configurations will be described below.

As shown in FIG. 4 , according to another embodiment of the presentdisclosure, conductive layers 135 are formed on a lower surface of afirst connection part 132 of an active layer 130 and a lower surface ofa second connection part 133 of the active layer 130 (e.g., between thedrain electrode 152 and the second connection part 133, and between thefirst connection part 132 and the connection electrode 153).

A conductive layer 135 provided on a lower surface of the firstconnection part 132 of the active layer 130 is provided in an end regionof the first connection part 132 to contact the connection electrode 153located below the conductive layer 135. Therefore, the conductive layer135 is provided between the lower surface of the first connection part132 of the active layer 130 and the upper surface of the connectionelectrode 153.

The conductive layer 135 provided on the lower surface of the secondconnection part 133 of the active layer 130 is provided in the endregion of the second connection part 133 to contact the drain electrode152 located below the conductive layer 135. Therefore, the conductivelayer 135 is provided between the lower surface of the second connectionpart 133 of the active layer 130 and the upper surface of the drainelectrode 152.

The conductive layer 135 is formed not to overlap the channel part 131and the gate electrode 151.

The conductive layer 135 can be made of a metal material havingexcellent conductivity. According to another embodiment of the presentdisclosure, the conductive layer 135 having excellent conductivity canbe additionally provided, thereby increasing the reaction speed of thethin film transistor and providing for faster switching.

FIG. 5 is a schematic cross-sectional view of the display deviceaccording to still another embodiment of the present disclosure, whichcorresponds to a cross-sectional view along A-A′ line of FIG. 1 .

FIG. 5 is the same as the display device according to FIG. 4 except thatthe structure of the gate insulating layer 140 is changed (e.g., thegate insulating layer 140 is larger and extends farther, similar to thearrangement in FIG. 3 ). Therefore, the same reference numerals areassigned to the same configuration, and only different configurationswill be described below.

As shown in FIG. 5 , the gate insulating layer 140 is formed not only inthe region between the gate electrode 151 and the channel part 131 ofthe active layer 130, but also on the lower surface of the firstconnection part 132 of the active layer 130, the lower surface of thesecond connection part 133 of the active layer 130, and the lowersurface of the buffer layer 120.

As described above, the gate insulating layer 140 can be additionallyprovided on a part of the upper surface of the connection electrode 153and can be additionally provided on a part of the upper surface of thedrain electrode 152.

FIG. 6 is a plan view illustrating a display device according to theother embodiment of the present disclosure.

FIG. 6 is the same as the display device according to FIG. 1 , exceptthat the first light blocking layer 115 is electrically connected to thegate electrode 151. Therefore, the same reference numerals are assignedto the same configuration, and only different configurations will bedescribed below.

According to FIG. 6 , the first light blocking layer 115 extends tooverlap the gate line 150, and the first light blocking layer 115 isconnected to at least one of the gate line 150 and the gate electrode151 through a fourth contact hole CH4.

The fourth contact hole CH4 is provided in the buffer layer 120 and thegate insulating layer 140, so that at least one of the gate line 150 andthe gate electrode 151 can extend through the fourth contact hole CH4 tocontact the first light blocking layer 115.

As described above, according to another embodiment of the presentdisclosure, since the first light blocking layer 115 is electricallyconnected to the gate electrode 151, the first light blocking layer 115can function as a second gate electrode, thereby obtaining a double gatestructure.

FIG. 7 is a plan view illustrating a display device according to anotherembodiment of the present disclosure.

FIG. 7 is the same as the display device according to FIG. 1 except thatthe first light blocking layer 115 is omitted. Therefore, the samereference numerals are assigned to the same configuration, and onlydifferent configurations will be described below.

Referring to FIG. 2 , the first light shielding layer 115 preventsexternal light incident through the upper surface of the first substrate100, which is a surface on which an image is displayed, from enteringthe channel part 131 of the active layer 130. Meanwhile, the channelpart 131 of the active layer 130 can be mainly affected by light emittedfrom the backlight 300 rather than the external light. Light emittedfrom the backlight 300 is blocked by the gate electrode 151 to preventthe light from being incident on the channel part 131 of the activelayer 130. Accordingly, the first light blocking layer 115 can beomitted as shown in FIG. 7 .

FIG. 8 is a plan view illustrating a display device according to stillanother embodiment of the present disclosure. Hereinafter, aconfiguration different from that of FIG. 1 described above will bedescribed.

As shown in FIG. 8 , a thin film transistor T driving the firstsub-pixel P1 is provided in the first sub-pixel P1 and the secondsub-pixel P2 adjacent thereto. Specifically, the gate electrode 151 isconfigured as a part of the gate line 150. That is, a portion of thegate line 150 overlapping the active layer 130 becomes the gateelectrode 151. The source electrode 111 is provided in the region of thesecond sub-pixel P2 and is configured as a part of the data line 110 inthe region of the second sub-pixel P2. The source electrode 111 can beconnected to the active layer 130 through a first contact hole CH1provided in the region of the second sub-pixel P2, and can be connectedto the connection electrode 153 through a second contact hole CH2provided in the region of the second sub-pixel P2. Accordingly, theconnection electrode 153 is also provided in the second sub-pixel P2.One end of the active layer 130 overlaps the drain electrode 152provided in the first sub-pixel P1, the other end of the active layer130 overlaps the source electrode 111 provided in the second sub-pixelP2, and a portion between one end and the other end of the active layer130 extends from the first sub-pixel P1 to the second sub-pixel P2 andoverlaps the gate electrode 151. Therefore, the end of the firstconnection part of the active layer 130 connected to the sourceelectrode 111 is provided in the second sub-pixel P2, the end of thesecond connection part of the active layer 130 connected to the drainelectrode 152 is provided in the first sub-pixel P1, and the channelpart of the active layer 130 overlapping the gate electrode 151 isprovided in an area overlapping the gate line 150.

Meanwhile, although FIG. 8 shows a structure in which the pixelelectrode 190 of the second sub-pixel P2 does not overlap the gate line150, the pixel electrode 190 of the second sub-pixel P2 can overlap thegate line 150.

In the embodiment of FIG. 8 , since the thin film transistor T isprovided in the first sub-pixel P1 and the second sub-pixel P2, theaperture ratio of the display device can be improved.

The cross-sectional structure of the embodiment of FIG. 8 can bevariously changed as shown in FIGS. 2 to 5 described above.

FIG. 9 is a plan view illustrating a display device according to stillanother embodiment of the present disclosure.

FIG. 9 is the same as the display device according to FIG. 8 , exceptthat the first light blocking layer 115 is electrically connected to thegate electrode 151. Therefore, the same reference numerals are assignedto the same configuration, and only different configurations will bedescribed below.

Referring to FIG. 9 , the first light blocking layer 115 is connected tothe gate line 150 through a fourth contact hole CH4. According toanother embodiment of the present disclosure, since the first lightblocking layer 115 is electrically connected to the gate electrode 151,the first light blocking layer 115 can function as a second gateelectrode, thereby obtaining a double gate structure.

FIG. 10 is a plan view illustrating a display device according to stillanother embodiment of the present disclosure. FIG. 10 is the same as thedisplay device according to FIG. 8 described above except that the firstlight blocking layer 115 is omitted.

FIG. 11 is a plan view illustrating a display device according to stillanother embodiment of the present disclosure.

FIG. 11 is different from FIG. 1 described above in that the secondlight blocking layer 210 overlaps the data line 110 and also overlapsthe gate line 150 (e.g., the second light blocking layer 210 can coverboth of the data line 110 and the gate line 150). Referring to FIG. 11 ,the second light blocking layer 210 is provided not to overlap the gateelectrode 151 and the drain electrode 152, thereby reducing the problemof decrease in an aperture ratio of the display device caused by theformation of the second light blocking layer 210.

The cross-sectional structure of the embodiment of FIG. 11 can bevariously changed as shown in FIGS. 2 to 5 described above.

In addition, in the embodiments of FIGS. 8 to 10 , the second lightblocking layer 210 can overlap the data line 110 and the gate line 150,and in this situation, the second light blocking layer 210 may notoverlap the drain electrode 152, thereby reducing the problem ofdecrease in an aperture ratio of the display device caused by theformation of the second light blocking layer 210. For example, thesecond light blocking layer 210 is spaced apart from the drain electrode152.

FIG. 12 is a plan view illustrating a display device according to stillanother embodiment of the present disclosure.

FIG. 12 is different from FIG. 1 described above in that the secondlight blocking layer 210 is omitted. Even if the second light blockinglayer 210 is omitted as shown in FIG. 12 , a problem of mixed lightbetween adjacent sub-pixels can be prevented, which will be describedlater with reference to a cross-sectional view. Meanwhile, the secondlight blocking layer 210 can be omitted in the above-describedembodiments of FIGS. 6 to 10 .

FIG. 13 is a schematic cross-sectional view of the display deviceaccording to still another embodiment of the present disclosure, whichcorresponds to a cross-sectional view along A-A′ line of FIG. 12 .

As shown in FIG. 13 , a display device in accordance with anotherembodiment of the present disclosure includes a first substrate 100, asecond substrate 200, and a backlight 300.

The first substrate 100 is the same as the first substrate 100 of FIG. 2, except that color filters 221 and 222 are additionally included.Therefore, the same reference numerals are assigned to the sameconfiguration, and only different configurations will be describedbelow.

The color filters 221 and 222 are provided between the passivation layer161 and the planarization layer 162. The first color filter 221 isprovided in the first sub-pixel, and the second color filter 222 isprovided in the second sub-pixel. The first color filter 221 and thesecond color filter 222 can overlap each other in the data line 110area, which is a boundary area between the first sub-pixel and thesecond sub-pixel.

When light emitted from the backlight 300 passes through the colorfilters 221 and 222, mixed light can occur in the boundary area betweenthe first sub-pixel and the second sub-pixel. Since the color filters221 and 222 are formed on the first substrate 100 and the distancebetween the color filters 221 and 222 and the data line 110 is close,the progress of mixed light can be blocked by the data line 110 toreduce the problem of the mixed light. For example, overlapping portionsof color filters 221 and 222 can act as a black matrix to block lightand prevent color mixing in a boundary area between sub-pixels.Accordingly, the second light blocking layer 210 for preventing mixingcan be omitted from the second substrate 200.

FIG. 14 is a schematic cross-sectional view of the display deviceaccording to still another embodiment of the present disclosure, whichcorresponds to a cross-sectional view along A-A′ line of FIG. 12 .

FIG. 14 is different from FIG. 13 described above in that theconfiguration of the second substrate 200 is changed. As shown in FIG.14 , a spacer 230, more specifically, a column spacer 230, is providedon an upper surface of the second substrate 200. The column spacer 230can be provided to perform a function of maintaining a cell gap betweenthe first substrate 100 and the second substrate 200 and to perform alight blocking function (e.g., performs dual functions). Accordingly,the column spacer 230 includes a light shielding material.

The column spacer 230 is formed to overlap the data line 110 of thefirst substrate 100, and in particular, can extend in the extendingdirection of the data line 110. That is, the column spacer 230 can havethe same pattern as the second light blocking layer 210 of FIG. 1 . Insome situations, the column spacer 230 can extend in the extendingdirection of the gate line 150 while overlapping the gate line 150 ofthe first substrate 100.

Also, in the embodiments of FIGS. 13 and 14 , the configuration of thefirst substrate 100 except for the color filters 221 and 222 can bevariously changed as shown in FIGS. 3 to 5 .

FIG. 15 is a plan view illustrating a display device according to stillanother embodiment of the present disclosure.

As shown in FIG. 15 , a display device in accordance with anotherembodiment of the present disclosure includes a first substrate 100, asecond substrate 200, and a driving unit 400.

The first substrate 100 constitutes an upper substrate, and the secondsubstrate 200 constitutes a lower substrate. The length of the firstsubstrate 100 can be longer than the length of the second substrate 200,and thus a portion of a lower surface of the first substrate 100 can beexposed without being covered by the second substrate 200. An electrodepad is provided on a part of a lower surface of the exposed firstsubstrate 100. The configurations provided on the first substrate 100and the second substrate 200 are the same as those of theabove-described various embodiments, and thus repeated descriptionsthereof will be omitted.

The driving unit 400 is mounted on a part of the lower surface of thefirst substrate 100 that is not covered by the second substrate 200, andis electrically connected to the electrode pad. The driving unit 400 caninclude a flexible printed circuit (FPC) film and a printed circuitboard (PCB). A chip can be formed on the flexible printed circuit (FPC)film to form a COF (Chip On Film) structure. Alternatively, a chip canbe formed on the first substrate 100 to form a chip on glass (COG)structure.

The above various embodiments relate to a liquid crystal display device,and the present disclosure can include other display devices having astructure in which a thin film transistor substrate is inverted.

Accordingly, the present disclosure can have the following advantages.

According to an embodiment of the present disclosure, since the channelpart of the active layer provided on the first substrate is covered bythe gate electrode, there is no need to form a separate light blockinglayer on the second substrate to cover the channel part of the activelayer, thereby improving the aperture ratio of the display device.

According to an embodiment of the present disclosure, since the secondlight blocking layer provided on the second substrate does not need tobe configured to overlap the thin film transistor region provided on thefirst substrate, the second light blocking layer can be formed tooverlap only the data line or the data line and the gate line, therebyimproving the aperture of the display device.

According to an embodiment of the present disclosure, a first lightblocking layer is additionally provided between the first substrate andthe channel part of the active layer, thereby protecting the channelpart from external light.

According to an embodiment of the present disclosure, a conductive layeris additionally formed on one surface of the first connection part andthe second connection part of the active layer, thereby improving areaction rate of the thin film transistor.

According to an embodiment of the present disclosure, a thin filmtransistor is divided into the first sub-pixel and the second sub-pixelsuch that the end of the first connection part of the active layer isprovided in the second sub-pixel, and the end of the second connectionpart of the active layer is provided in the first sub-pixel, therebyimproving the aperture ratio of the display device.

It will be apparent to those skilled in the art that varioussubstitutions, modifications, and variations are possible within thescope of the present disclosure without departing from the spirit andscope of the present disclosure. Therefore, the scope of the presentdisclosure is represented by the following claims, and all changes ormodifications derived from the meaning, range and equivalent concept ofthe claims should be interpreted as being included in the scope of thepresent disclosure.

What is claimed is:
 1. A display device comprising: a first substratehaving an upper surface and a lower surface facing the upper surface,the upper surface including a display surface; an active layer disposedon the lower surface of the first substrate, the active layer includinga channel part, a first connection part connected to a first side of thechannel part, and a second connection part connected to a second side ofthe channel part; a gate electrode disposed under the active layer andoverlapping with the channel part; a second substrate disposed under thegate electrode; a liquid crystal layer disposed between the firstsubstrate and the second substrate; and a backlight disposed under thesecond substrate, wherein the gate electrode is disposed between thechannel part and the backlight.
 2. The display device according to claim1, wherein light emitted from the backlight is blocked by the gateelectrode after passing through the second substrate and the liquidcrystal layer, and is prevented from being incident on the channel part3. The display device according to claim 1, further comprising a firstlight blocking layer disposed between the first substrate and the activelayer, wherein the first light blocking layer overlaps with the channelpart of the active layer.
 4. The display device according to claim 3,wherein the first light blocking layer is made of a conductive materialand is electrically connected to the gate electrode through a contacthole.
 5. The display device according to claim 1, further comprising: agate line and a data line disposed to cross each other on the lowersurface of the first substrate; and a second light shielding layerdisposed on an upper surface of the second substrate and overlappingwith at least one of the gate line and the data line.
 6. The displaydevice according to claim 5, further comprising: a source electrodeconnected to the data line and the first connection part of the activelayer; and a drain electrode connected to the second connection part ofthe active layer, wherein the second light blocking layer does notoverlap with the drain electrode.
 7. The display device according toclaim 1, further comprising: a gate line and a data line disposed tocross each other on the lower surface of the first substrate; and acolumn spacer disposed on an upper surface of the second substrate andoverlapping with at least one of the gate line and the data line, thecolumn spacer including a light shielding material.
 8. The displaydevice according to claim 1, further comprising a color filter disposedon the lower surface of the first substrate, wherein a separate lightshielding layer is not provided on the second substrate.
 9. The displaydevice according to claim 1, wherein a length of the first substrate islonger than a length of the second substrate, and wherein a driving unitis attached on an exposed part of the lower surface of the firstsubstrate that is not covered by the second substrate.
 10. The displaydevice according to claim 1, further comprising: a source electrodeconnected to the first connection part of the active layer; a drainelectrode connected to the second connection part of the active layer;and a pixel electrode connected to the drain electrode, wherein thesource electrode is disposed between the first substrate and the activelayer, and wherein the drain electrode is disposed between the activelayer and the second substrate.
 11. The display device according toclaim 10, further comprising a connection electrode connecting the firstconnection part of the active layer with the source electrode.
 12. Thedisplay device according to claim 1, further comprising: a firstsub-pixel and a second sub-pixel disposed on the first substrate,wherein an end of the first connection part of the active layer is inthe second sub-pixel, and an end of the second connection part of theactive layer is in the first sub-pixel.
 13. A display device comprising:a first substrate having an upper surface and a lower surface facing theupper surface, the upper surface including a display surface; an activelayer disposed on the lower surface of the first substrate, the activelayer including a channel part, a first connection part connected to afirst side of the channel part, and a second connection part connectedto a second side of the channel part; a gate electrode spaced apart fromthe active layer and overlapping with the channel part; a sourceelectrode connected to the first connection part of the active layer; adrain electrode connected to the second connection part of the activelayer; and a pixel electrode connected to the drain electrode, whereinthe active layer is disposed between the lower surface of the firstsubstrate and the gate electrode.
 14. The display device according toclaim 13, wherein the source electrode is in contact with an uppersurface of the active layer, and wherein the drain electrode is incontact with a lower surface of the active layer.
 15. The display deviceaccording to claim 14, wherein the source electrode is disposed betweenthe first substrate and the active layer, and wherein the drainelectrode is disposed between the active layer and the pixel electrode.16. The display device according to claim 13, further comprising abuffer layer disposed between the source electrode and the active layer,wherein the source electrode is connected to the first connection partof the active layer through a contact hole in the buffer layer.
 17. Thedisplay device according to claim 13, further comprising a connectionelectrode connecting the first connection part of the active layer withthe source electrode.
 18. The display device according to claim 17,further comprising a buffer layer disposed between the source electrodeand the active layer, wherein a first side of the connection electrodeis connected to the source electrode through the contact hole in thebuffer layer, and a second side of the connection electrode is disposedon the first connection part of the active layer.
 19. The display deviceaccording to claim 13, further comprising a first light blocking layerdisposed between the first substrate and the active layer, the firstlight blocking layer overlapping with the channel part of the activelayer.
 20. The display device according to claim 19, wherein the firstlight blocking layer is made of a conductive material and iselectrically connected to the gate electrode through a contact hole, andwherein the first light blocking layer and the gate electrode from adouble gate structure.
 21. The display device according to claim 13,further comprising a gate insulating layer disposed between the activelayer and the gate electrode, wherein the gate insulating layer overlapswith the channel part, a portion of the first connection part and aportion of the second connection part.
 22. The display device accordingto claim 13, further comprising a conductive layer disposed between thefirst connection part of the active layer and the drain electrode,wherein the conductive layer does not to overlap the gate electrode. 23.The display device according to claim 13, further comprising: a gateline disposed on the lower surface of the first substrate and connectedto the gate electrode; a data line disposed on the lower surface of thefirst substrate; a second substrate facing the lower surface of thefirst substrate; and a second light shielding layer disposed on an uppersurface of the second substrate facing the lower surface of the firstsubstrate, the second light shielding layer overlapping with the dataline on the lower surface of the first substrate.
 24. The display deviceaccording to claim 23, wherein the second light blocking layer overlapswith the gate line and extends along a length of the gate line, andwherein the second light blocking layer does not overlap the drainelectrode.
 25. The display device according to claim 13, furthercomprising: a color filter disposed between the drain electrode and thepixel electrode; and a second substrate facing the lower surface of thefirst substrate, wherein a separate light blocking layer is not providedon the second substrate.
 26. The display device according to claim 13,further comprising: a first sub-pixel and a second sub-pixel disposed onthe first substrate, wherein an end of the first connection part of theactive layer is in the second sub-pixel, and an end of the secondconnection part of the active layer is in the first sub-pixel.